Physical Simulation Platform and Detection Method for Grounding Line Selection Device Detection

Abstract

The embodiment of the present application provides a physical simulation platform and a detection method for detecting a grounding line selection device. The platform includes: a 380V system and a 10kV system; the 380V system includes: a fault generator, a 380V bus, and a simulation line connected to the 380V bus. The simulation line includes a current transformer interface, a 10kV system access point, a parameter unit, and a load unit connected in sequence. A fault access point is also provided on the simulation line; the fault access point is used to connect the fault generator; the 10kV system is connected to the 10kV system access point, and the current transformer interface is used to access the grounding line selection device. The structure of the present application is reliable and has high reusability, can perform performance detection on grounding line selection devices of different manufacturers or models, ensure the application reliability of the grounding line selection device, effectively improve the convenience, efficiency, and reliability of the detection of the grounding line selection device, and reduce the detection cost.

Description

Technical Field

[0001] This application relates to the technical field of power equipment, and specifically relates to a physical simulation platform and a detection method for detecting earthing line selection devices. Background Art

[0002] As the dependence of people's production and life on electricity increases day by day, the safety and stability of the distribution network become more and more important. In a small current grounding system, when a grounding fault occurs, due to the small fault current, it is difficult to determine the faulty line. The method of manual pulling test leads to a long fault handling time and power outage of non-faulty lines. By installing an earthing line selection device, the faulty line can be directly determined, the fault handling time can be reduced, and the power outage range can be reduced. Therefore, the reliability of the earthing line selection device is crucial. Since the fault characteristic quantities in a small current grounding system are not obvious and the algorithms of various types of earthing line selection devices are different, the positioning accuracy is also very different. To ensure the reliable operation of the distribution network, it is necessary to carry out in-network detection on the earthing line selection device.

[0003] However, the existing methods for detecting the performance of earthing line selection devices usually involve directly applying external signals to the earthing line selection devices. There are few detection devices dedicated to detecting earthing line selection devices, and the existing small number of detection devices for detecting earthing line selection devices also have problems such as poor structural reliability or inability to be reused. Moreover, due to different technical levels of each manufacturer, the products produced are uneven. Therefore, the existing detection devices for earthing line selection devices cannot ensure the application reliability of earthing line selection devices. Summary of the Invention

[0004] Aiming at the problems in the prior art, this application provides a physical simulation platform and a detection method for detecting earthing line selection devices. The physical simulation platform for detecting earthing line selection devices has a reliable structure and high reusability, can detect the performance of earthing line selection devices of different manufacturers or models, and can effectively improve the convenience, efficiency and reliability of detecting earthing line selection devices and reduce the detection cost on the basis of ensuring the application reliability of earthing line selection devices.

[0005] To solve the above technical problems, this application provides the following technical solutions:

[0006] In the first aspect, this application provides a physical simulation platform for detecting earthing line selection devices, including: a 380V system and a 10kV system;

[0007] The 380V system includes: a fault generator, a 380V busbar, and an analog line connected to the 380V busbar. The analog line includes a current transformer interface, a 10kV system access point, a parameter unit for simulating the capacitance of the corresponding analog line to the ground, and a load unit for simulating the user load, which are connected in sequence. A fault access point is also provided on the analog line; the fault access point is used to connect to the fault generator;

[0008] The 10kV system is connected to the 10kV system access point to simulate a 10kV system fault. The current transformer interface is used to access the ground fault selection device to perform performance detection on the ground fault selection device based on the 380V system.

[0009] Further, each of the analog lines includes three analog branches, and each analog branch is respectively connected to the three-phase lines of the 380V busbar one-to-one;

[0010] A current transformer interface for accessing the ground fault selection device is provided on each of the analog branches.

[0011] Further, the fault generator includes: a ground fault unit;

[0012] The ground fault unit includes: a ground fault access point, a main switch, an arc grounding fault switch, a metal and resistance grounding fault switch, a first grounding resistance unit, and a second grounding resistance unit;

[0013] The ground fault access point, the main switch, the arc grounding fault switch, and the second grounding resistance unit are connected in sequence. The metal and resistance grounding fault switch is connected in parallel with the arc grounding fault switch, and both the arc grounding fault switch and the metal and resistance grounding fault switch are connected to the first grounding resistance unit;

[0014] The ground fault access point is used to connect to the fault access point.

[0015] Further, the first grounding resistance unit includes: a first grounding resistance branch, a second grounding resistance branch, a third grounding resistance branch, and a fourth grounding resistance branch connected in parallel, and the first grounding resistance branch, the second grounding resistance branch, the third grounding resistance branch, and the fourth grounding resistance branch are all grounded;

[0016] Among them, the first grounding resistance branch includes a switch, and the second grounding resistance branch to the fourth grounding resistance branch each include a switch and a resistor connected in series;

[0017] Each of the switches in the first grounding resistance unit is connected to the arc grounding fault switch and the metal and resistance grounding fault switch.

[0018] Further, the second grounding resistance unit includes: a grounding resistance branch, and three grounded resistors connected in sequence to one side of the grounding resistance branch. The grounding resistance branch includes a resistor and a switch connected in series;

[0019] The other side of the grounding resistance branch is connected to an arc grounding fault switch and a metal and resistance grounding fault switch;

[0020] The grounding resistance branch is in parallel with a switch. The branch formed by the grounding resistance branch and an adjacent resistor is in parallel with a switch. Another branch formed by the grounding resistance branch and two adjacent resistors in sequence is in parallel with a switch.

[0021] Further, the fault generator includes: a short - circuit fault unit;

[0022] The short - circuit fault unit includes: a phase - electricity selection switch and three short - circuit branches. A short - circuit fault access point is provided on one side of each short - circuit branch, and a switch and a resistor are connected in sequence on the other side. Each of the short - circuit branches is respectively in parallel with a branch formed by a connected switch and resistor;

[0023] The phase - electricity selection switch is arranged between one side of each of the short - circuit branches and the corresponding short - circuit fault access point;

[0024] Each of the resistors in the short - circuit fault unit is grounded via a switch;

[0025] The short - circuit fault access point is used to connect to the fault access point.

[0026] Further, the parameter unit includes: at least one grounding capacitance sub - unit. Each grounding capacitance sub - unit includes three grounding capacitance branches, and each of the grounding capacitance branches is respectively connected one - to - one to each of the analog branches;

[0027] Each of the grounding capacitance branches is provided with a connected capacitor and switch, and each of the capacitors in the grounding capacitance sub - unit is grounded.

[0028] Further, the load unit includes: a first load sub - unit and a second load sub - unit;

[0029] The first load sub - unit includes: three first load branches, and each of the first load branches is respectively connected one - to - one to each of the analog branches. Each of the first load branches is provided with a connected switch and resistor;

[0030] The first load sub - unit includes: three second load branches, and each of the second load branches is respectively connected one - to - one to each of the analog branches;

[0031] Each of the second load branches is provided with a switch, and the switches in each of the second load branches are respectively connected to their corresponding resistors or are all connected to a start button.

[0032] Further, it further includes: a 380V power supply, and this 380V power supply is connected to the 380V bus through an isolation transformer.

[0033] Further, it further includes: two 380V bus voltage transformers both connected to the 380V bus.

[0034] Further, it further includes: a neutral point unit, and this neutral point unit is connected to the 380V bus through a grounding transformer;

[0035] The neutral point unit includes a first resistor, a second resistor and an arc suppression coil connected in parallel, and the resistance values of the first resistor and the second resistor are different.

[0036] Further, it further includes: a capacitance parameter unit;

[0037] The capacitance parameter unit includes a first ground capacitance simulation sub-unit and a second ground capacitance simulation sub-unit;

[0038] The first ground capacitance simulation sub-unit includes three first capacitance branches, and each of the first capacitance branches is respectively connected to the three-phase lines of the 380V bus one-to-one; each of the first capacitance branches includes a capacitor, a switch and a disconnector connected in sequence;

[0039] The second ground capacitance simulation sub-unit includes three second capacitance branches, and each of the second capacitance branches is respectively connected to the three-phase lines of the 380V bus one-to-one; each of the second capacitance branches includes a capacitor and a disconnector connected in sequence;

[0040] The capacitors in the capacitance parameter unit are all grounded.

[0041] Further, a fault access point and a transfer type arc suppression device are connected to the 380V bus;

[0042] The transfer type arc suppression device includes three grounded switches connected in parallel, and each of the switches in the transfer type arc suppression device is respectively connected to the three-phase lines of the 380V bus one-to-one.

[0043] In a second aspect, the present application provides a method for detecting a ground wire selection device. The method for detecting a ground wire selection device is implemented by using the physical simulation platform for detecting a ground wire selection device described above. The method for detecting a ground wire selection device includes:

[0044] Connect the ground fault selection device to the current transformer interface through a test line; connect the 10kV system to the 10kV system access point, and connect the fault generator to the fault access point;

[0045] Control the 380V system to simulate a ground fault condition, and verify whether the ground fault selection device can identify the corresponding ground fault and give an alarm. Among them, the ground fault condition includes at least one of the following: two-phase short circuit fault, three-phase short circuit fault, the grounding fault unit simulates a metallic grounding fault, grounding faults through different resistance values, arc grounding fault, and arc grounding fault through a transition resistance.

[0046] Operate the physical simulation platform for detecting the ground fault selection device to verify whether the ground fault selection device malfunctions. Among them, the operations include at least one of the following: switching lines, switching operations, and load transfer.

[0047] As can be seen from the above technical solutions, the physical simulation platform and detection method for detecting the ground fault selection device provided by this application. The physical simulation platform for detecting the ground fault selection device includes: a 380V system and a 10kV system; the 380V system includes: a fault generator, a 380V bus, and a simulated line connected to the 380V bus. The simulated line includes a 10kV system access point connected in sequence, a parameter unit for simulating the capacitance of the corresponding simulated line to the ground, and a load unit for simulating the user load. A fault access point is also provided on the simulated line; the fault access point is used to connect the fault generator; the 10kV system includes a high-voltage feeder unit for connecting the ground fault selection device. The high-voltage feeder unit is connected to the 10kV system access point to perform performance detection on the ground fault selection device based on the 380V system. The physical simulation platform for detecting the ground fault selection device has a reliable structure and high reusability, can perform performance detection on ground fault selection devices of different manufacturers or models, and can effectively improve the convenience, efficiency, and reliability of ground fault selection device detection on the basis of ensuring the application reliability of the ground fault selection device, and reduce the detection cost. Brief Description of the Drawings

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0049] Figure 1A It is a schematic diagram of the first connection structure of the physical simulation platform for detecting the ground fault selection device in the embodiments of the present application.

[0050] Figure 1B It is a schematic diagram of the second connection structure of the physical simulation platform for detecting the grounding line selection device in the embodiment of the present application.

[0051] Figure 2 It is a schematic diagram of the connection structure of the 380V system in the physical simulation platform for detecting the grounding line selection device in the embodiment of the present application.

[0052] Figure 3 It is a schematic diagram of the specific component connection structure of the 380V system in the physical simulation platform for detecting the grounding line selection device in the embodiment of the present application.

[0053] Figure 4 It is a schematic diagram of the structure of the high-voltage feeder unit in the physical simulation platform for detecting the grounding line selection device in the embodiment of the present application.

[0054] Figure 5 It is a schematic diagram of the structure of the grounding fault unit in the physical simulation platform for detecting the grounding line selection device in the embodiment of the present application.

[0055] Figure 6 It is a schematic diagram of the structure of the short-circuit fault unit in the physical simulation platform for detecting the grounding line selection device in the embodiment of the present application.

[0056] Figure 7 It is a schematic diagram of the flow of the grounding line selection device detection method in the embodiment of the present application.

[0057] Reference numerals in the drawings:

[0058] 1. 380V system;

[0059] 11. Fault generator;

[0060] 12. 380V busbar;

[0061] 13. Simulation line;

[0062] 131. 10kV system access point;

[0063] 132. Fault access point;

[0064] 1321. First fault access point;

[0065] 1322. Second fault access point;

[0066] 1323. Third fault access point;

[0067] 1324. Fourth fault access point;

[0068] 1325. Fifth fault access point;

[0069] 133. Parameter unit;

[0070] 1331. First parameter unit;

[0071] 1332. Second parameter unit;

[0072] 1333. Third parameter unit;

[0073] 1334. Fourth parameter unit;

[0074] 134. Load unit;

[0075] 1341. First load unit;

[0076] 1342. Second load unit;

[0077] 1343. Third load unit;

[0078] 1344. Fourth load unit;

[0079] 14. First line;

[0080] 15. Second line;

[0081] 16. Third line;

[0082] 17. Fourth line;

[0083] 18. Current transformer interface;

[0084] 2. 10kV system;

[0085] 22. High-voltage feeder unit;

[0086] 221. Secondary harmonic suppression test interface;

[0087] 222. Primary harmonic suppression test interface;

[0088] 223. 10kV feeder;

[0089] 4. Grounding line selection device;

[0090] 5. 380V power supply;

[0091] 6. Transfer type arc suppression device;

[0092] 7. Bus voltage transformer unit;

[0093] 8. Neutral point unit;

[0094] 91. First ground capacitance simulation sub-unit;

[0095] 92. Second ground capacitance simulation sub-unit. Detailed implementation manners

[0096] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0097] In one or more embodiments of this application, a grounding line selection device refers to a small current grounding system. Since the single-phase grounding fault current is small and it is impossible to determine which line the fault occurs on, it is often necessary for maintenance personnel to disconnect each line one by one to determine the faulty line. The grounding line selection device utilizes the characteristics that there are significant differences in fault characteristic quantities such as transient and steady-state zero-sequence currents between the faulty line and the non-faulty lines to achieve accurate identification of the faulty line. The grounding line selection device has the functions of identifying the faulty line, fault alarm, and tripping the faulty line. The grounding line selection device can also be called a small current grounding line selection device, and this device is applicable to single-phase grounding line selection in 3KV - 66KV neutral ungrounded or neutral grounded through a resistor or arc suppression coil system.

[0098] To improve the structural reliability and reusability of the equipment for detecting the grounding line selection device, an embodiment of this application provides a physical simulation platform for detecting the grounding line selection device. Refer to Figure 1A , the physical simulation platform for detecting the grounding line selection device specifically includes the following:

[0099] A 380V system 1 and a 10kV system 2; the 380V system 1 specifically includes: a current transformer interface 18, a fault generator 11, a 380V bus 12, and a simulation line 13 connected to the 380V bus 12. The simulation line 13 specifically includes a 10kV system access point 131, a parameter unit 133 for simulating the capacitance to ground of the corresponding simulation line, and a load unit 134 for simulating the user load connected in sequence; a fault access point 132 is also provided on the simulation line 13; the fault access point 132 is used to connect the fault generator 11; the current transformer interface 18 is used to access the grounding line selection device 4 to perform performance detection on the grounding line selection device 4 based on the 380V system 1; the 10kV system 2 is connected to the 10kV system access point 131 to simulate a 10kV system fault. Refer to Figure 1B, the 10kV system 2 specifically further includes a high-voltage feeder unit 22 for connecting a secondary harmonic elimination device, a primary harmonic elimination device, and a distribution fault indicator. The high-voltage feeder unit 22 is connected to the 10kV system access point 131 to perform performance detection on the secondary harmonic elimination device, the primary harmonic elimination device, and the distribution fault indicator based on the 380V system 1. And a recorder is provided on the high-voltage feeder unit 22 to collect the oscillogram waveforms of the secondary harmonic elimination device and the primary harmonic elimination device by applying the recorder during the performance detection of the secondary harmonic elimination device and the primary harmonic elimination device.

[0100] See Figures 2 to 6 , the 380V bus 12 in the 380V system 1 specifically refers to a simulated 380V bus, including three-phase lines: the first line A, the second line B, and the third line C. Correspondingly, each simulated line 13 includes three simulated branches, and each simulated branch is respectively connected one-to-one to the first line A, the second line B, and the third line C of the 380V bus.

[0101] It can be understood that Figure 2 the same components shown on the three lines are represented by one symbol, and it can be understood that the components on these three lines can all be represented by this symbol. For example, the disconnecting switch QS-X1 on the first line 14 means that disconnecting switches are respectively provided on each simulated branch of the first line 14. And for the convenience of identification and description, the disconnecting switches on each simulated branch of the first line 14 are uniformly marked as QS-X1.

[0102] In a specific example of the present application, see Figures 2 to 6 , the simulated branch 13 can be four, namely the first line 14, the second line 15, the third line 16, and the fourth line 17.

[0103] The current transformer interface 18 on the first line 14 may include current transformers X1TAa, X1TAb, and X1Tac; the current transformer interface 18 on the second line 15 may include current transformers X2TAa, X2TAb, and X2TAc; the current transformer interface 18 on the third line 16 may include current transformers X3TAa, X3TAb, and X3TAc; the current transformer interface 18 on the fourth line 17 may include current transformers X4TAa, X4TAb, and X4Tac.

[0104] First, the first line 14 specifically includes a disconnecting switch QS-X1 and a circuit breaker QF-X1 that are connected to each other. Each analog branch of the first line 14 is respectively provided with a current transformer X1TAa, a current transformer X1TAb, and a current transformer X1TAc that are connected to the circuit breaker QF-X1. The current transformers X1TAa, X1TAb, and X1TAc are all connected to the current transformer X1TAo, and the current transformer X1Tao is respectively connected to the 10 kV system access points 131 of each analog branch of the first line 14. The 10 kV system access points 131 of each analog branch are respectively connected to their corresponding second fault access points 1322, a parameter unit 133 for simulating the ground capacitance of the corresponding analog line, and a load unit 134 for simulating the user load. The second fault access point 1322 is used to connect to the fault generator 11. Among them, the parameter unit 133 corresponding to the first line 14 can specifically select the first parameter unit 1331, and the load unit 134 corresponding to the first line 14 can specifically select the first load unit 1341.

[0105] The first parameter unit 1331 specifically includes: at least one ground capacitance sub-unit. Each ground capacitance sub-unit includes three ground capacitance branches, and each of the ground capacitance branches is respectively connected to each of the analog branches in a one-to-one manner. One of the ground capacitance branches is provided with a capacitor C11 and a switch KM-C11 that are connected to each other, and the capacitance value C 11 = 5.1 μF; another ground capacitance branch is provided with a capacitor C12 and a switch KM-C12 that are connected to each other, and the capacitance value C 12 = 5.1 μF, and each capacitor in the ground capacitance sub-unit is grounded. In addition, the current value Ic1 of the first parameter unit 1331 is 2 A.

[0106] The first load unit 1341 specifically includes: a first load sub-unit and a second load sub-unit; the first load sub-unit specifically includes: three first load branches, and each of the first load branches is respectively connected to each of the analog branches in a one-to-one manner; each of the first load branches is provided with a switch KM-X1R1 and a resistor R11 that are connected to each other, and the specification of the resistor R11 is 55 Ω, 4 A; the first load sub-unit also specifically includes: three second load branches, and each of the second load branches is respectively connected to each of the analog branches in a one-to-one manner; each of the second load branches is provided with a switch KM-X1M, and the switches KM-X1M in each of the second load branches are respectively connected to a start button SF1, and the current value I L1 = 1 A, and the load current of the first load unit 1341 is 5 A.

[0107] Second, the second line 15 specifically includes a disconnecting switch QS-X2 and a circuit breaker QF-X2 that are connected to each other. Current transformers X2TAa, X2TAb, and X2TAc connected to the circuit breaker QF-X2 are respectively provided on each analog branch of the second line 15. The current transformers X2TAa, X2TAb, and X2TAc are all connected to a current transformer X2TAo, and the current transformer X2TAo is respectively connected to the 10 kV system access points 131 of each analog branch of the second line 15. The 10 kV system access points 131 of each analog branch are respectively connected to their corresponding third fault access points 1323, a parameter unit 133 for simulating the ground capacitance of the corresponding analog line, and a load unit 134 for simulating the user load. The third fault access point 1323 is used to connect to the fault generator 11. Among them, the parameter unit 133 corresponding to the second line 15 can specifically select the second parameter unit 1332, and the load unit 134 corresponding to the second line 15 can specifically select the second load unit 1342.

[0108] The second parameter unit 1332 specifically includes: at least one ground capacitance sub-unit. Each ground capacitance sub-unit includes three ground capacitance branches, and each of the ground capacitance branches is respectively connected one-to-one to each of the analog branches. One of the ground capacitance branches is provided with a capacitor C21 and a switch KM-C21 that are connected to each other, and the capacitance value C 21 = 15 μF; another ground capacitance branch is provided with a capacitor C22 and a switch KM-C22 that are connected to each other, and the capacitance value C 22 = 15 μF, and each capacitor in the ground capacitance sub-unit is grounded. In addition, the current value Ic2 of the second parameter unit 1332 is 6 A.

[0109] The second load unit 1342 specifically includes: a first load sub-unit and a second load sub-unit; the first load sub-unit specifically includes: three first load branches, and each of the first load branches is respectively connected one-to-one to each of the analog branches; each of the first load branches is provided with a switch KM-X2R1 and a resistor R21 that are connected to each other, and the specification of the resistor R21 is 44 Ω, 5 A; the first load sub-unit also specifically includes: three second load branches, and each of the second load branches is respectively connected one-to-one to each of the analog branches; each of the second load branches is provided with a switch KM-X2R2, and the switches KM-X2R2 in each of the second load branches are respectively connected to their corresponding resistors R22, and the specification of the resistor R22 is 44 Ω, 5 A, and the load current of the second load unit 1342 is 10 A.

[0110] Thirdly, the third line 16 specifically includes a disconnecting switch QS-X3 and a circuit breaker QF-X3 that are connected to each other. Current transformers X3TAa, X3TAb, and X3TAc connected to the circuit breaker QF-X3 are respectively provided on each analog branch of the third line 16. The current transformers X3TAa, X3TAb, and X3TAc are all connected to a current transformer X3TAo, and the current transformer X3TAo is respectively connected to the 10 kV system access points 131 of each analog branch of the third line 16. The 10 kV system access points 131 of each analog branch are respectively connected to a parameter unit 133 for simulating the ground capacitance of the corresponding analog line, their respective fourth fault access points 1324, and a load unit 134 for simulating the user load. The fourth fault access point 1324 is used to connect to the fault generator 11. Among them, the parameter unit 133 corresponding to the third line 16 can specifically select a third parameter unit 1333, and the load unit 134 corresponding to the third line 16 can specifically select a third load unit 1343.

[0111] The third parameter unit 1333 specifically includes: at least one ground capacitance sub-unit. Each ground capacitance sub-unit includes three ground capacitance branches, and each of the ground capacitance branches is respectively connected to each of the analog branches in a one-to-one manner. One of the ground capacitance branches is provided with a capacitor C31 and a switch KM-C31 that are connected to each other, and the capacitance value C 31 = 5.1 μF; another ground capacitance branch is provided with a capacitor C32 and a switch KM-C32 that are connected to each other, and the capacitance value C 32 = 15 μF, and each capacitor in the ground capacitance sub-unit is grounded. In addition, the current value Ic3 of the third parameter unit 1333 is 4 A.

[0112] The third load unit 1343 specifically includes: a first load sub-unit and a second load sub-unit. The first load sub-unit specifically includes: three first load branches, and each of the first load branches is respectively connected to each of the analog branches in a one-to-one manner. Each of the first load branches is provided with a switch KM-X3R1 and a resistor R31 that are connected to each other, and the specification of the resistor R31 is 55 Ω, 5 A. The first load sub-unit also specifically includes: three second load branches, and each of the second load branches is respectively connected to each of the analog branches in a one-to-one manner. Each of the second load branches is provided with a switch KM-X3R2, and the switches KM-X3R2 in each of the second load branches are respectively connected to their corresponding resistors R32, and the specification of the resistor R32 is 55 Ω, 4 A, and the load current of the third load unit 1343 is 8 A.

[0113] Fourthly, the fourth line 17 specifically includes a disconnecting switch QS-X4 and a circuit breaker QF-X4 that are connected to each other. Current transformers X4TAa, X4TAb, and X4TAc connected to the circuit breaker QF-X4 are respectively provided on each analog branch of the fourth line 17. The current transformers X4TAa, X4TAb, and X4TAc are all connected to the current transformer X4TAo, and the current transformer X4TAo is respectively connected to the 10 kV system access points 131 of each analog branch of the fourth line 17. The 10 kV system access points 131 of each analog branch are respectively connected to a parameter unit 133 for simulating the ground capacitance of the corresponding analog line, their respective fifth fault access points 1325, and a load unit 134 for simulating the user load. The fifth fault access point 1325 is used to connect to the fault generator 11. Among them, the parameter unit 133 corresponding to the fourth line 17 can specifically select the fourth parameter unit 1334, and the load unit 134 corresponding to the fourth line 17 can specifically select the fourth load unit 1344.

[0114] The fourth parameter unit 1334 specifically includes: a ground capacitance sub-unit, which includes three ground capacitance branches, and each of the ground capacitance branches is respectively connected one-to-one to each of the analog branches; the ground capacitance branch is provided with a capacitor C41 and a switch KM-C41 that are connected to each other, and the capacitance value C4 = 15 μF; and each capacitor in the ground capacitance sub-unit is grounded. In addition, the current value Ic4 of the fourth parameter unit 1334 is 3 A.

[0115] The fourth load unit 1344 specifically includes: a first load sub-unit and a second load sub-unit; the first load sub-unit specifically includes: three first load branches, and each of the first load branches is respectively connected one-to-one to each of the analog branches; each of the first load branches is provided with a switch KM-X4R1 and a resistor R41 that are connected to each other, and the specification of the resistor R41 is 44 Ω, 5 A; the first load sub-unit also specifically includes: three second load branches, and each of the second load branches is respectively connected one-to-one to each of the analog branches; each of the second load branches is provided with a switch KM-X4M, and the switches KM-X4M in each of the second load branches are respectively connected to a start button SF2, and the current value I L2 = 1 A, and the load current of the fourth load unit 1344 is 6 A.

[0116] In addition, refer to Figures 2 to 6, the physical simulation platform for detecting the grounding line selection device further specifically includes: a 380V power supply 5, and the 380V power supply 5 can be connected to the 380V bus through an isolation transformer ZT. The circuit where the 380V power supply 5 is located specifically includes: a first power supply line connected to the first line A, a second power supply line connected to the second line B, and a third power supply line connected to the third line C. The first power supply line, the second power supply line, and the third power supply line are all provided with disconnecting switches QS-Z1 connected to each other. Each disconnecting switch QS-Z1 is respectively connected to its corresponding switch KM-Z1. Each switch KM-Z1 is respectively connected one-to-one to a current transformer Z1TA, a current transformer Z2TA, and a current transformer Z3TA. Each of the switches KM-Z1 and the corresponding current transformer is directly connected to the 380V bus voltage transformer ZTV through a circuit breaker QF-PT. The current transformer Z1TA, the current transformer Z2TA, and the current transformer Z3TA are all connected to the isolation transformer ZT, and the isolation transformer ZT is respectively connected to the corresponding disconnecting switches QS-Z2 on the first power supply line, the second power supply line, and the third power supply line. Each disconnecting switch QS-Z2 is respectively connected one-to-one to a switch KM-Z2. Each switch KM-Z2 is respectively connected to the corresponding current transformers Z2TAa, Z2TAb, and Z2Tac on the first power supply line, the second power supply line, and the third power supply line. And the current transformers Z2TAa, Z2TAb, and Z2Tac are all connected to a current transformer Z2TAa.

[0117] A first fault access point 1321 and a transfer type arc suppression device 6 are also connected to the 380V bus of the physical simulation platform for detecting the grounding line selection device; the transfer type arc suppression device 6 specifically includes three grounded switches connected in parallel, namely a switch KM-XHC, a switch KM-XHB, and a switch KM-XHA. And the switches KM-XHC, KM-XHB, and KM-XHA in the transfer type arc suppression device are respectively connected one-to-one to the third line C, the second line B, and the first line A of the 380V bus.

[0118] The physical simulation platform for detecting the grounding line selection device further specifically includes: two bus voltage transformer units 7. Each bus voltage transformer unit 7 includes a 380V bus voltage transformer connected to the 380V bus, namely a 380V bus voltage transformer ZTV1 and a 380V bus voltage transformer ZTV2. The 380V bus voltage transformer ZTV1 is respectively connected to the 380V bus through a switch KM-PT2 and a circuit breaker QF-PT2; the 380V bus voltage transformer ZTV2 is connected to the 380V bus through a circuit breaker QF-PT1.

[0119] The physical simulation platform for detecting the grounding line selection device further specifically includes: a neutral point unit 8, which can be connected to the 380V bus through a grounding transformer JDB; the neutral point unit specifically includes a first resistor, a second resistor, and an arc suppression coil connected in parallel, and the resistance values of the first resistor and the second resistor are different. The first resistor is a small resistor NR1, and the small resistor NR1 is connected to a current transformer NTA through a switch KM-N1. The second resistor is a high-resistance NR2, and the high-resistance NR2 is connected to the current transformer NTA through a switch KM-N2. The arc suppression coil NXH is connected to the current transformer NTA through a switch KM-N3. The current transformer NTA is connected to the grounding transformer JDB, and the grounding transformer JDB is connected to the 380V bus through a switch KM-JDB and a circuit breaker QF-JDB.

[0120] The physical simulation platform for detecting the grounding line selection device further specifically includes: a capacitance parameter unit, and the capacitance parameter unit specifically includes a first ground capacitance simulation sub-unit 91 and a second ground capacitance simulation sub-unit 92.

[0121] The first ground capacitance simulation sub-unit 91 specifically includes three first capacitance branches, and each first capacitance branch is respectively connected to the three-phase lines of the 380V bus one by one; each of the first capacitance branches includes a capacitor, a switch, and a disconnector connected in sequence; specifically, the capacitor MCa2 on one first capacitance branch is connected to the disconnector QF-MC2A through the switch KM-MC2, the capacitor MCb2 on another first capacitance branch is connected to the disconnector QF-MC2B through the switch KM-MC2, and the capacitor MCc2 on another first capacitance branch is connected to the disconnector QF-MC2C through the switch KM-MC2. The disconnectors QF-MC2A, QF-MC2B, and QF-MC2C are all connected to the 380V bus, and the resistance value Cm1 of the first ground capacitance simulation sub-unit 91 is 2.55 μF.

[0122] The second ground capacitance simulation sub-unit 92 specifically includes three second capacitance branches, and each second capacitance branch is respectively connected to the three-phase lines of the 380V bus one by one; each of the second capacitance branches includes a capacitor and a disconnector connected in sequence; specifically, the capacitor MCa1 on one second capacitance branch is connected to the 380V bus through the disconnector QF-MC1A, the capacitor MCb1 on another second capacitance branch is connected to the 380V bus through the disconnector QF-MC1B, and the capacitor MCc1 on another second capacitance branch is connected to the 380V bus through the disconnector QF-MC1C. The capacitors in the capacitance parameter unit are all grounded, and the resistance value Cm1 of the second ground capacitance simulation sub-unit 92 is 5.1 μF.

[0123] In an embodiment of the physical simulation platform for detecting the grounding line selection device of the present application, the high-voltage feeder unit 22 specifically includes: a high-voltage feeder access point, a switch, a step-up transformer, a first fuse, and a 10 kV feeder 223 connected in sequence; the high-voltage feeder unit also specifically includes: a current transformer, a second fuse, and a voltage transformer connected in sequence to the 10 kV feeder, and the primary side of the voltage transformer is grounded; a secondary harmonic elimination test interface 221 is provided between the secondary side of the voltage transformer and the second fuse; the high-voltage feeder access point is connected to the 10 kV system access point.

[0124] See Figure 4 , there are three groups of the high-voltage feeder access points, one of which is access point A L and access point A N , which is used to connect to the 10 kV system access point 131 of the first analog branch in the analog line 13, and the first analog branch is a line connected to the first line A of the 380 V bus 12; the second is access point B L and access point B N , which is used to connect to the 10 kV system access point 131 of the second analog branch in the analog line 13, and the second analog branch is a line connected to the second line B of the 380 V bus 12; the third is access point C L and access point C N , which is used to connect to the 10 kV system access point 131 of the third analog branch in the analog line 13, and the third analog branch is a line connected to the third line C of the 380 V bus 12.

[0125] The access point A L in the high-voltage feeder unit 22, access point A N , access point B L , access point B N , access point C L and access point C NIt is connected to the step-up transformer PT-XGs through the switch KM-XG. The step-up transformer PT-XGs is connected to the first fuse FU-XGs corresponding to each group of high-voltage feeder access points respectively. The first fuse FU-XGs is respectively connected to the current transformer TA-XGc corresponding to each group of high-voltage feeder access points. The current transformer TA-XGc is connected to the second fuse FU-XGc corresponding to it. The second fuses FU-XGc are all connected to the secondary side of the voltage transformer PT-XGc. A secondary harmonic elimination test interface 221 is provided between the secondary side of the voltage transformer PT-XGc and the second fuse FU-XGc; the secondary harmonic elimination test interface 221 is used to connect to a secondary harmonic elimination device. The primary side of the voltage transformer PT-XGc is grounded, and a primary harmonic elimination test interface 222 is provided on the primary side of the voltage transformer PT-XGc. The primary harmonic elimination test interface 222 is used to connect to a primary harmonic elimination device.

[0126] In an embodiment of the physical simulation platform for detecting the grounding line selection device of the present application, the fault generator specifically includes: a grounding fault unit;

[0127] See Figure 5 , the grounding fault unit specifically includes: a grounding fault access point JGZ, a main switch KM-JZ-1, a current transformer JTA, an arc grounding fault switch KM-J1, a metal and resistance grounding fault switch KM-J2, a first grounding resistance unit, and a second grounding resistance unit; the grounding fault access point JGZ, the main switch KM-JZ-1, the arc grounding fault switch KM-J1, and the second grounding resistance unit are connected in sequence. The metal and resistance grounding fault switch KM-J2 is connected in parallel with the arc grounding fault switch KM-J1, and both the arc grounding fault switch KM-J1 and the metal and resistance grounding fault switch KM-J2 are connected to the first grounding resistance unit; the grounding fault access point JGZ is used to connect to the fault access point 132.

[0128] Among them, the first grounding resistance unit specifically includes: a first grounding resistance branch, a second grounding resistance branch, a third grounding resistance branch, and a fourth grounding resistance branch connected in parallel, and the first grounding resistance branch, the second grounding resistance branch, the third grounding resistance branch, and the fourth grounding resistance branch are all grounded;

[0129] Among them, the first grounding resistance branch specifically includes a switch KM-J3 with a resistance value R = 0Ω; the second grounding resistance branch specifically includes a series-connected switch KM-J4 and a resistor J1R with a resistance value R = 7.5Ω; the third grounding resistance branch specifically includes a series-connected switch KM-J5 and a resistor J2R with a resistance value R = 15Ω; the fourth grounding resistance branch specifically includes a series-connected switch KM-J6 and a resistor J3R with a resistance value R = 30Ω. Each of the switches in the first grounding resistance unit is connected to the arc grounding fault switch and the metal and resistor grounding fault switch.

[0130] Among them, the second grounding resistance unit specifically includes: a grounding resistance branch, and three grounded resistors connected in sequence to one side of the grounding resistance branch, namely a resistor J7R with a resistance value R = 60Ω, a resistor J6R with a resistance value R = 60Ω, a resistor J5R with a resistance value R = 60Ω, a resistor J4R with a resistance value R = 60Ω, and a switch KM-J10. A switch KM-J9 is connected in parallel with the switch KM-J10 and the resistor J4R, a switch KM-J8 is connected in parallel with the resistor J5R, the resistor J4R, and the switch KM-J10, and a switch KM-J7 is connected in parallel with the resistor J6R, the resistor J5R, the resistor J4R, and the switch KM-J10.

[0131] In an embodiment of the physical simulation platform for detecting the grounding line selection device of the present application, the fault generator specifically includes: a short-circuit fault unit;

[0132] See Figure 6, the short - circuit fault unit specifically includes: a phase - electricity selection switch KM - DZ and three short - circuit branches. And on one side of each short - circuit branch, there is a short - circuit fault access point DGZ, and on the other side, each is connected to a corresponding switch and a resistor through its respective current transformers DTAa, DTAb, and DTAc; each of the short - circuit branches is respectively connected in parallel with a branch composed of a connected switch and resistor; the phase - electricity selection switch KM - DZ is arranged between one side of each of the short - circuit branches and the corresponding short - circuit fault access point; each resistor in the short - circuit fault unit is grounded through a switch; the short - circuit fault access point is used to connect to the fault access point 132. Specifically, the current transformer DTAa is sequentially connected to the switch KM - D2 - A and a resistor with a resistance value R = 3.8Ω, and the branch where the switch KM - D2 - A and the resistor with a resistance value R = 3.8Ω are located is connected in parallel with the branch where the switch KM - D1 - A and a resistor with a resistance value R = 1.8Ω are located; the current transformer DTAb is sequentially connected to the switch KM - D2 - B and a resistor with a resistance value R = 3.8Ω, and the branch where the switch KM - D2 - B and the resistor with a resistance value R = 3.8Ω are located is connected in parallel with the branch where the switch KM - D1 - B and a resistor with a resistance value R = 1.8Ω are located; the current transformer DTAc is sequentially connected to the switch KM - D2 - C and a resistor with a resistance value R = 3.8Ω, and the branch where the switch KM - D2 - C and the resistor with a resistance value R = 3.8Ω are located is connected in parallel with the branch where the switch KM - D1 - C and a resistor with a resistance value R = 1.8Ω are located.

[0133] To improve the structural reliability and reusability of the equipment for detecting the grounding line - selection device, an embodiment of the present application provides a grounding line - selection device detection method implemented by using the physical simulation platform for detecting the grounding line - selection device provided in the present application. Refer to Figure 7 , the grounding line - selection device detection method specifically includes the following content:

[0134] Step 100: Connect the grounding line - selection device to the current transformer interface through a test line; connect the 10kV system to the 10kV system access point, and connect the fault generator to the fault access point;

[0135] Step 200: Control the 380V system to simulate the grounding - fault conditions, and verify whether the grounding line - selection device can identify the corresponding grounding fault and alarm. Among them, the grounding - fault conditions include at least one of two - phase short - circuit fault, three - phase short - circuit fault, the grounding - fault unit simulating a metallic grounding fault, grounding faults through different resistance values, arc - grounding fault, and arc - grounding fault through a transition resistance.

[0136] Step 300: Operate the physical simulation platform for detecting the grounding line selection device to verify whether the grounding line selection device malfunctions, where the operation includes at least one of switching lines, switching operations, and load transfer.

[0137] As can be seen from the above description, the grounding line selection device detection method provided by the embodiments of the present application can perform performance detection on grounding line selection devices of different manufacturers or models, and thus can effectively improve the convenience, efficiency, and reliability of grounding line selection device detection, reduce the detection cost, and ensure the application reliability of the grounding line selection device.

[0138] To further illustrate the solution, in a specific application example of the present application, a distribution physical simulation platform is used to simulate ferromagnetic resonance and various fault conditions. The platform includes a 380V system and a 10kV system. The 380V system includes a main transformer, a bus, an outgoing line unit, a neutral point grounding module, a short-circuit fault simulation unit, a grounding fault simulation unit, a control unit, and a protection unit; the 10kV system includes a step-up transformer, a simulated line, a PT, and a capacitor. The 380V system simulates various operating and fault conditions, and the 10kV system realizes the performance detection of the distribution device.

[0139] The system is powered by a 380V power supply and supplies power to the 380V simulation bus through an isolation transformer ZT. The bus leads out the system neutral point through a grounding transformer JDB, and the system neutral point grounding method (ungrounded, high-resistance grounded, low-resistance grounded, arc suppression coil grounded, four choices) is selected through a transfer switch. For detailed description, see the neutral point device description in the module description. ZTV1 and ZTV2 are 380V bus voltage transformers for measuring the bus voltage. KM-MC2 is a capacitor parameter unit for simulating the true ground capacitance parameter of the bus.

[0140] The platform includes 4 simulated lines. The simulated lines include 10kV system access points (colored dots in the CAD drawing), fault access points, parameter units, and load units. The 10kV system access points can be connected to a high-voltage feeder unit to realize the performance detection of devices such as 10kV fault indicators and harmonic elimination devices; the fault access points can be connected to a grounding fault generator or a short-circuit fault generator to simulate various faults; the parameter unit simulates the true line parameters of the line; the load unit is used to simulate the user load.

[0141] The fault mode (grounding or short circuit, two choices) is selected through a selector switch; the short-circuit fault mode (50A three-phase; 50A two-phase, two choices) is selected through a transfer switch; the fault simulation unit is controlled by a changeover switch according to the fault simulation type, and the control unit relay selectively controls according to the fault type (high-resistance grounding, metal grounding, arc grounding, two-phase short circuit, three-phase short circuit), but it is not allowed for the above two faults to occur simultaneously (software interlock);

[0142] When the system grounding method is "ungrounded neutral point, low-resistance grounding, high-resistance grounding, grounding through arc suppression coil", the closing time of the control node for fault types (high-resistance grounding, metal grounding, arc grounding, two-phase short circuit, three-phase short circuit) is 1s (time adjustable).

[0143] When a single-phase grounding fault occurs in the system, after 0.3S (time adjustable) of delay since the fault occurs is calculated by the controller, the system quickly switches on and off the bus arc suppression device.

[0144] (1) Control unit and protection device

[0145] The control unit controls according to different functions of the system. A centralized control unit is set in each cabinet of the power transformation cabinet, neutral point complete set cabinet, first feeder cabinet, second feeder cabinet, and fault simulation cabinet, and independent modular control is carried out using Siemens S7-200PLC; communicate with the background host through the on-site communication system, and the operator can complete the debugging and fault simulation of the physical simulation platform at the engineer station.

[0146] Separate protection devices are configured for the main transformer incoming and outgoing lines and feeder lines, with voltage and current protection functions; with accurate voltage and current measurement functions.

[0147] A separate measuring device is configured for each section of feeder line outlet switch, with voltage and current protection functions; with accurate voltage and current measurement functions.

[0148] (2) Technical indicators

[0149] System power supply: three-phase, 380V, 100A, 50Hz;

[0150] Full-load working current of the line: 10A;

[0151] Short-circuit current of the line: 1000A;

[0152] System capacitive current: 30A;

[0153] Secondary voltage of the normal operating voltage transformer PT: 100V;

[0154] Secondary current of the normal operating current transformer CT: <=5A;

[0155] Overall measurement accuracy of the system: 0.5 level.

[0156] (3) Main equipment and parameters

[0157] 3.1 Cabinet dimensions (GGD)

[0158] Power transformation cabinet: 1000×800×2200mm (width × depth × height);

[0159] Neutral point complete set of switchgear: 1200×800×2200mm (width × depth × height)

[0160] Feeder line 1 switchgear: 1000×800×2200mm (width × depth × height);

[0161] Feeder line 2 switchgear: 1000×800×2200mm (width × depth × height)

[0162] High-voltage feeder switchgear: 1500×800×2200mm (width × depth × height);

[0163] Fault simulation switchgear: 1200×800×2200mm (width × depth × height);

[0164] Fault recording screen: 800×800×2200mm (width × depth × height);

[0165] Comprehensive test screen: 800×800×2200mm (width × depth × height).

[0166] 3.2. Main transformer

[0167] Rated voltage: 380V;

[0168] Rated current: 60A;

[0169] Turn ratio: 380V / 380V;

[0170] Insulation type: Epoxy resin casting;

[0171] Rated capacity: 40kVA;

[0172] Group: YN / zn11;

[0173] 1min power frequency withstand voltage: 35kV.

[0174] 3.3. Arc suppression coil

[0175] Rated voltage: 220V;

[0176] Rated current: 33A;

[0177] Adjustment range: 3~30A;

[0178] 1min power frequency withstand voltage: 3kV.

[0179] 3.4. Neutral point resistor (high resistance)

[0180] Resistance value: 220Ω;

[0181] Short-time rated current: 20A.

[0182] 3.5. Neutral point resistor (low resistance)

[0183] Resistance value: 3.34 Ω;

[0184] Short-time rated current: 66 A, 10 S.

[0185] 3.6. Class I load

[0186] Load type: Resistor;

[0187] Rated current: 3 A, 2 A, 1 A;

[0188] Temperature rise: 30 K.

[0189] Design description:

[0190] Single-group design parameters: 1 A, 220 Ω, 220 W * 3, star connection.

[0191] Selection: Single-piece parameters 5 A, 220 Ω, 5500 W, 3 pieces in star connection (1 group). The power of a single resistor is 25 times the rated power, mainly considering its surface temperature rise;

[0192] Based on the control of single-piece parameters 5 A, 220 Ω, 5500 W, 3 pieces in star connection (1 group), a single group of 1 A is achieved.

[0193] There are 4 groups of resistive loads, combined as 3 A, 2 A, 1 A. The first group of load IR1 = 1 A, the second group of load IR2 = 2 A, the third group of load IR3 = 1 A, and the fourth group of load IR4 = 3 A.

[0194] 3.7. Class II load

[0195] Load type: Motor

[0196] Rated current: 0.3 A, 0.6 A

[0197] Design description:

[0198] Design parameters of the air supply fan: Three-phase, 380 V, 0.3 A, 100 W per group;

[0199] Design parameters of the air supply fan: Three-phase, 380 V, 0.2 A, 40 W for 4 groups (feeder cabinet and fault simulation cabinet);

[0200] There are a total of three groups of impact loads (motors). The first group of load I1 = 0.3 A, the second group of load IR2 = 0.6 A, and the third group of load IR3 = 0.9 A.

[0201] 3.8. Fault simulation resistor

[0202] Type: Resistor;

[0203] Rated current: 100 A (5 s), 50 A (5 s), 5 A.

[0204] 3.9. Inductor

[0205] Rated current: 50A;

[0206] Voltage drop: 2% for a single one, two in series for a single line;

[0207] Rated voltage: 0.38 kV;

[0208] Rated capacity: 18.5 KW.

[0209] 3.10. Power capacitor

[0210] Type: Three-phase capacitor;

[0211] Rated current: 5A;

[0212] Rated voltage: 1.9 kV;

[0213] Operating voltage: 0.38 kV;

[0214] Rated capacitance: 16.5 uF;

[0215] Rated capacity: 14.5 Kvar.

[0216] 3.11. Step-up transformer

[0217] Rated voltage: 10.5 kV;

[0218] Voltage ratio: 0.38 / / 10 / ;

[0219] Insulation type: Epoxy resin casting (three-phase combination Y / y0);

[0220] Rated capacity: 20 VA.

[0221] 3.12. Voltage transformer - high-voltage measurement

[0222] Rated voltage: 10 kV;

[0223] Voltage ratio: 10 / √3 / 0.1 / √3 / 0.1 / 3 (three-phase combination Y0 / y0 / △, 0.2 level);

[0224] Insulation type: Epoxy resin casting, three-phase five-column type;

[0225] Rated capacity: 15 VA.

[0226] 3.13. Voltage transformer - busbar low-voltage measurement

[0227] Rated voltage: 0.38 kV;

[0228] Voltage transformation ratio: 0.38 / √3 / 0.1 / √3 / 0.1 / 3 (three-phase combined Y0 / y0 / △, class 0.2);

[0229] Insulation type: non-encapsulated structure, three-phase five-column type;

[0230] Rated capacity: 20VA.

[0231] 3.14. High-voltage fuse

[0232] Model: XRNP-12 / 0.5A, including fuse and base;

[0233] Quantity: 6 sets, for step-up transformer and 10kV voltage transformer.

[0234] 3.15. Circuit breaker

[0235] Molded case circuit breaker 1 (main circuit + outgoing line + short-circuit fault simulation)

[0236] Brand: Schneider;

[0237] Model: CVS160B;

[0238] Order number: LV516303;

[0239] Type: fixed front connection, 3-pole, In = 160, electromagnetic TM-D protection;

[0240] Dimensions: (W x H x D, mm) = 105x161x86;

[0241] Quantity: to be determined.

[0242] 3.16. Current transformer

[0243] Model: LMZ1-0.66;

[0244] Parameters: 10VA, 100 / 5, 0.2S;

[0245] Insulation type: epoxy casting.

[0246] 3.17. Fault recording

[0247] Sampling rate:

[0248] The maximum sampling speed of the host single-channel A / D is 100KSBS, and the actual sampling speed is 5kHz (100 points per cycle). Record 4 cycles before the fault and 8 cycles after the fault.

[0249] Fault recording start condition:

[0250] Zero-sequence voltage startup: As long as the zero-sequence voltage of the system exceeds the set startup value (secondary value, default 10V, adjustable), the host immediately starts recording waveforms;

[0251] Phase current startup: As long as the phase current at any point in the system exceeds the set startup value (secondary value, default 2A, adjustable), the host immediately starts recording waveforms;

[0252] Setting the startup value: The file for setting the startup value is in the "CTPT" sub-file in the XDL folder on the host's NANDFLASH disk. Open the "CTPT" sub-file, and there are 4 lines of numbers inside. The third line of numbers is the zero-sequence voltage startup value; the fourth line of numbers is the phase current startup value. You can change the startup value according to actual needs and save it after modification.

[0253] (4) Module unit

[0254] 4.1. Interface reservation

[0255] Several access points are reserved in the system. All these access points are multiplexed interfaces and can access various modules such as single-phase grounding faults, short-circuit faults, power sources, loads, and connections.

[0256] 4.2. Load unit

[0257] Through the access port, various types of load units can be conveniently accessed.

[0258] Configure 1 group of load units, which consists of a continuously adjustable resistor, inductor, and capacitor load system, generating a maximum load current of 10A. It can simulate various power conditions such as three-phase load imbalance, sudden load addition and removal, different power factor leading and lagging.

[0259] 4.3. Fault simulation unit

[0260] Through the access port, the fault simulation unit module can be accessed, including short-circuit faults and single-phase grounding faults.

[0261] Short-circuit fault unit: It can simulate two-phase short circuits and three-phase short circuits, and the short-circuit current is controllable. A protection device is configured. Through the switch, two-phase phase-to-phase faults or three-phase phase-to-phase faults can be selected, and the fault resistance of the phase-to-phase fault can be selected in the switchable area.

[0262] Grounding fault unit: The single-phase grounding fault unit can simulate the following single-phase grounding faults: metallic grounding, grounding through different resistance values, arcing grounding, arcing grounding through a transition resistance, etc. The grounding resistance selection switch can select a grounding resistance adjustment from 0 - 240Ω. Through different switch combinations, metallic grounding, grounding through different resistance values, metallic arcing grounding, and arcing grounding through a transition resistance faults can be simulated.

[0263] 4.4. Neutral point equipment

[0264] An independent grounding transformer is configured to draw out the neutral point of the system. The neutral point can be made ungrounded (all switches are open), grounded through a low resistance, or grounded through an arc suppression coil by means of a transfer switch. The grounding transformer JDB adopts a Z-type connection with a capacity of 8.8 kVA; the arc suppression coil has a capacity of 8.8 kVA, 11 steps, manual adjustment, with a current compensation range of 10 - 40 A and a step difference not exceeding 3 A, and manual adjustment; a low resistance of 3.34 Ω 66 A 10 s is selected; a high resistance of 220 Ω 1 A 10 s is selected; and a signal source interface is reserved.

[0265] 4.5. High-voltage feeder unit

[0266] The high-voltage feeder unit boosts 380 V to 10 kV through a step-up transformer. The 10 kV feeder 223 is a closed ring, which can be used to install actual 10 kV distribution fault indicators for the performance verification of the distribution fault indicators; the step-up transformer is a 10 kV true-type PT, with an interface for installing a primary harmonic eliminator reserved at the neutral point of the primary side and an interface for a secondary harmonic eliminator reserved at the secondary side, which can be used for the performance verification of the harmonic eliminator.

[0267] (V) Platform function description

[0268] The platform simulates the switching of 4 lines and the operation of disconnecting switches by opening and closing the QS-X1-4 and QF-X1-4 switches; the inductive load is put into operation by closing the switches KM-X1M and KM-X4M, and the resistive load is put into operation by the switches KM-X1R1 to KM-X4R1, so as to simulate the load change and adjust the load current magnitude.

[0269] The performance detection test of the grounding line selection device is carried out as follows:

[0270] The grounding line selection device is connected through the X1TAa-c, X2TAa-c, X3TAa-c, and X4TAa-c interfaces and connected by test lines.

[0271] The 380 V system relies on the short-circuit fault unit to simulate two-phase short circuit and three-phase short circuit, and the grounding fault unit to simulate metallic grounding, grounding through different resistances, arc grounding, and arc grounding through a transition resistance fault, etc. By setting various faults on different lines (the fault parameters are shown in Table 1), verify whether the grounding line selection device can correctly identify and alarm; perform operations such as switching lines, switching operations, and load transfer, and verify whether the grounding line selection device malfunctions. Since the platform simulates the real 10 kV fault and operating condition environment, it is applicable to the performance detection of various principle and type fault indicators.

[0272] Table 1 Evaluation parameters of the grounding line selection device

[0273] Grounding position Busbar, feeder Grounding resistance / Ω 0 (metallic), 60 (medium resistance), 180 (high resistance) Grounding method Continuous grounding, arcing grounding Fault mode Single-phase grounding, phase-to-phase short circuit

[0274] The performance test of the grounding line selection device is carried out as follows:

[0275] 1) Fault line selection test:

[0276] Set faults with various fault parameters as shown in Table 1 on different lines respectively to check whether the grounding line selection device can correctly locate the faults.

[0277] Test steps:

[0278] a. Connect the grounding line selection device to the platform;

[0279] b. Start the platform and set the fault parameters;

[0280] c. Put into the fault unit and record whether the grounding line selection device operates correctly;

[0281] d. Remove the fault;

[0282] e. Change the fault parameters and repeat steps c - d;

[0283] f. Complete all types of faults at all fault positions;

[0284] g. Shut down the platform and end the test;

[0285] h. Summarize the correctness of the operation of the grounding line selection device.

[0286] Detection and evaluation criteria:

[0287] The line selection accuracy for short - circuit faults, metallic grounding faults, and medium - resistance grounding faults should reach 100%, the accuracy for arcing grounding faults should reach 80%, and the accuracy for high - resistance grounding faults should reach 70%; after the grounding line selection device identifies a fault, it should be able to correctly send an alarm and send data to the master station at the same time.

[0288] It should be noted that in this text, relational terms are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element. The orientation or positional relationship indicated by terms such as "above", "below", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. Unless otherwise expressly specified and defined, the terms "mounted", "connected", "coupled" shall be construed broadly, e.g., it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, or an electrical connection; it may be a direct connection, or an indirect connection through an intermediate medium, and may be a communication between two elements inside. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0289] In the description of the present invention, a large number of specific details are set forth. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail so as not to obscure the understanding of this description. Similarly, it should be understood that, in order to streamline the disclosure of the present invention and assist in understanding one or more of the various inventive aspects, in the foregoing description of the exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected by the claims, the inventive aspects lie in less than all of the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the present invention. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present invention is not limited to any single aspect, nor to any single embodiment, nor to any arbitrary combination and / or permutation of these aspects and / or embodiments. Moreover, each aspect and / or embodiment of the present invention may be used alone or in combination with one or more other aspects and / or their embodiments.

[0290] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A physical simulation platform for detecting a grounding line selection device, characterized in that, Including: 380V system and 10kV system; The 380V system includes: a fault generator, a 380V busbar, and an analog line connected to the 380V busbar. The analog line includes a current transformer interface, a 10kV system access point, a parameter unit for simulating the capacitance of the corresponding analog line to the ground, and a load unit for simulating the user load, which are connected in sequence. A fault access point is also provided on the analog line; the fault access point is used to connect to the fault generator; The 10kV system is connected to the 10kV system access point to simulate a 10kV system fault. The current transformer interface is used to access a ground fault selection device to perform performance detection on the ground fault selection device based on the 380V system; The 10kV system also specifically includes a high-voltage feeder unit for connecting a secondary harmonic elimination device, a primary harmonic elimination device, and a distribution fault indicator. The high-voltage feeder unit is connected to the 10kV system access point to perform performance detection on the secondary harmonic elimination device, the primary harmonic elimination device, and the distribution fault indicator based on the 380V system. A recorder is provided on the high-voltage feeder unit to collect the recorded waveforms of the secondary harmonic elimination device and the primary harmonic elimination device by applying the recorder during the performance detection of the secondary harmonic elimination device and the primary harmonic elimination device.

2. The physical simulation platform for detecting the grounding line selection device according to claim 1, characterized in that Each of the analog lines includes three analog branches, and each analog branch is respectively connected to the three-phase lines of the 380V busbar in a one-to-one manner; Each of the analog branches is provided with the current transformer interface for accessing the ground fault selection device.

3. The physical simulation platform for detecting the grounding line selection device according to claim 1, characterized in that The fault generator includes: a ground fault unit; The ground fault unit includes: a ground fault access point, a main switch, an arc grounding fault switch, a metal and resistance grounding fault switch, a first grounding resistance unit, and a second grounding resistance unit; The ground fault access point, the main switch, the arc grounding fault switch, and the second grounding resistance unit are connected in sequence. The metal and resistance grounding fault switch is connected in parallel with the arc grounding fault switch, and both the arc grounding fault switch and the metal and resistance grounding fault switch are connected to the first grounding resistance unit; The ground fault access point is used to connect to the fault access point.

4. The physical simulation platform for detecting the grounding line selection device according to claim 3, characterized in that, The first grounding resistance unit includes: a first grounding resistance branch, a second grounding resistance branch, a third grounding resistance branch, and a fourth grounding resistance branch connected in parallel, and the first grounding resistance branch, the second grounding resistance branch, the third grounding resistance branch, and the fourth grounding resistance branch are all grounded; Among them, the first grounding resistance branch includes a switch, and the second grounding resistance branch to the fourth grounding resistance branch each include a switch and a resistor connected in series; Each of the switches in the first grounding resistance unit is connected to the arc grounding fault switch and the metal and resistance grounding fault switch.

5. The physical simulation platform for detecting the grounding line selection device according to claim 3, characterized in that, The second grounding resistance unit includes: a grounding resistance branch, three grounded resistors connected in sequence to one side of the grounding resistance branch. The grounding resistance branch includes a resistor and a switch connected in series; The other side of the grounding resistance branch is connected to the arc grounding fault switch and the metal and resistance grounding fault switch; The grounding resistance branch is in parallel with a switch. The branch composed of the grounding resistance branch and an adjacent resistor is in parallel with a switch. Another branch composed of the grounding resistance branch and two adjacent resistors in sequence is in parallel with a switch.

6. The physical simulation platform for detecting the grounding line selection device according to claim 1 or 3, characterized in that, The fault generator includes: a short-circuit fault unit; The short-circuit fault unit includes: a phase electricity selection switch and three short-circuit branches. A short-circuit fault access point is provided on one side of each short-circuit branch, and a switch and a resistor are sequentially connected on the other side. Each of the short-circuit branches is respectively in parallel with a branch composed of a connected switch and resistor corresponding to it; The phase electricity selection switch is arranged between one side of each of the short-circuit branches and the corresponding short-circuit fault access point; Each of the resistors in the short-circuit fault unit is grounded via a switch; The short-circuit fault access point is used to connect to the fault access point.

7. The physical simulation platform for detecting the grounding line selection device according to claim 2, characterized in that, The parameter unit includes: at least one grounding capacitance sub-unit. Each grounding capacitance sub-unit contains three grounding capacitance branches, and each of the grounding capacitance branches is respectively connected one-to-one to each of the analog branches; Each of the grounding capacitance branches is provided with a connected capacitor and switch, and each of the capacitors in the grounding capacitance sub-unit is grounded.

8. The physical simulation platform for detecting the grounding line selection device according to claim 2, characterized in that, The load unit includes: a first load sub-unit and a second load sub-unit; The first load sub-unit includes: three first load branches, and each of the first load branches is respectively connected one-to-one to each of the analog branches; Each of the first load branches is provided with a connected switch and resistor; The first load sub-unit includes: three second load branches, and each of the second load branches is respectively connected one-to-one to each of the analog branches; Each of the second load branches is provided with a switch, and the switches in each of the second load branches are respectively connected to their corresponding resistors or are all connected to a start button.

9. The physical simulation platform for detecting the grounding line selection device according to claim 1, characterized in that, It further includes: A 380V power supply, and this 380V power supply is connected to the 380V bus via an isolation transformer.

10. The physical simulation platform for detecting the grounding line selection device according to claim 1, characterized in that, It further includes: Two 380V bus voltage transformers both connected to the 380V bus.

11. The physical simulation platform for detecting the grounding line selection device according to claim 1, characterized in that It further includes: A neutral point unit, and this neutral point unit is connected to the 380V bus via a grounding transformer; The neutral point unit includes a first resistor, a second resistor and an arc suppression coil connected in parallel, and the resistance values of the first resistor and the second resistor are different.

12. The physical simulation platform for detecting the grounding line selection device according to claim 1, wherein, It further includes: A capacitance parameter unit; The capacitance parameter unit includes a first ground capacitance simulation sub-unit and a second ground capacitance simulation sub-unit; The first ground capacitance simulation sub-unit includes three first capacitance branches, and each first capacitance branch is respectively connected one-to-one to the three-phase lines of the 380V bus; Each of the first capacitance branches includes a sequentially connected capacitor, switch and disconnecting switch; The second ground capacitance simulation sub-unit includes three second capacitance branches, and each second capacitance branch is respectively connected one-to-one to the three-phase lines of the 380V bus; Each of the second capacitance branches includes a sequentially connected capacitor and disconnecting switch; The capacitors in the capacitance parameter unit are all grounded.

13. The physical simulation platform for detecting the grounding line selection device according to claim 1, characterized in that, A fault access point and a transfer type arc suppression device are connected to the 380V bus; The transfer type arc suppression device includes three grounded switches connected in parallel, and each of the switches in the transfer type arc suppression device is respectively connected to the three-phase lines of the 380V bus one-to-one.

14. A method for detecting an earthing line selection device, characterized in that, The grounding line selection device detection method is implemented by using the physical simulation platform for grounding line selection device detection as described in any one of claims 1 to 13. The grounding line selection device detection method includes: Connect the grounding line selection device to the current transformer interface through a test line; connect the 10kV system to the 10kV system access point, and connect the fault generator to the fault access point; Control the 380V system to simulate a grounding fault condition and verify whether the grounding line selection device can identify the corresponding grounding fault and give an alarm. Among them, the grounding fault condition includes at least one of the following: two-phase short circuit fault, three-phase short circuit fault, grounding fault unit simulating a metallic grounding fault, grounding fault through different resistance values, arc grounding fault, and arc grounding fault through a transition resistance. Operate the physical simulation platform for grounding line selection device detection to verify whether the grounding line selection device malfunctions. Among them, the operation includes at least one of the following: switching lines, switching operations, and load transfer.

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